AC Loss Reduction in Coated Conductors

The application of superconducting technology will be a major factor in the improvement of the nation¿s electrical system. However, traditional coated conductors (CCs) on metal tapes suffer AC losses due to their high aspect ratio. Substrate magnetic and eddy current losses also are unavoidable with current CC technologies. In addition, from the application stand point, customers need thin round wire (like commonly-used copper wire) or multi-filament cables instead of the wide-tape CCs. This project will explore the use of coated sapphire fiber for low-AC-loss multifilament cable applications. Sapphire fiber with a diameter of 100-150 µm and an aspect ratio of 1 would provide an ideal substrate for YBCO growth. The low aspect ratio, non¬magnetic, non-conductive, and low-dielectric-constant nature of sapphire fiber would provide extremely low AC loss in CC applications. Moreover, the substrate magnetic and eddy current losses would be completely eliminated. Commercial Applications and other Benefits as described by the awardee: The use of sapphire fiber as substrate should lead to a revolution in the coated conductor industry. The superconductor cable industry would benefit in applications where AC loss is the major concern, for example motors, transformers, and generators.